Extract option building to standalone method. Update help to use method.

plugins/commands/serve/service/command_service.rb

@@ -7,17 +7,9 @@ module VagrantPlugins
         end
 
         def help(*args)
-          plugin_name = args.last.metadata["plugin_name"]
-          plugin = Vagrant::Plugin::V2::Plugin.manager.commands[plugin_name.to_sym].to_a.first
-          if !plugin
-            raise "Failed to locate command plugin for: #{plugin_name}"
-          end
-          $stashed_opts = nil
-          klass = Class.new(plugin.call)
-          klass.class_eval { def parse_options(opts); $stashed_opts = opts; nil; end };
-          klass.new(['-h'], {}).execute
+          options = command_options_for(args.last.metadata["plugin_name"])
           Hashicorp::Vagrant::Sdk::Command::HelpResp.new(
-            help: $stashed_opts.help()
+            help: options.help
           )
         end
 
@@ -42,31 +34,10 @@ module VagrantPlugins
         end
 
         def flags(*args)
-          plugin_name = args.last.metadata["plugin_name"]
-          plugin = Vagrant::Plugin::V2::Plugin.manager.commands[plugin_name.to_sym].to_a.first
-          if !plugin
-            raise "Failed to locate command plugin for: #{plugin_name}"
-          end
-
-          # Create a new anonymous class based on the command class
-          # so we can modify the setup behavior
-          klass = Class.new(plugin.call)
-
-          # Update the option parsing to store the provided options, and then return
-          # a nil value. The nil return will force the command to call help and not
-          # actually execute anything.
-          klass.class_eval do
-            def parse_options(opts)
-              Thread.current.thread_variable_set(:command_options, opts)
-              nil
-            end
-          end
-
-          # Execute the command to populate our options
-          klass.new([], {}).execute
+          options = command_options_for(args.last.metadata["plugin_name"])
 
           # Now we can build our list of flags
-          flags = Thread.current.thread_variable_get(:command_options).top.list.find_all { |o|
+          flags = options.top.list.find_all { |o|
             o.is_a?(OptionParser::Switch)
           }.map { |o|
             Hashicorp::Vagrant::Sdk::Command::Flag.new(
@@ -86,6 +57,38 @@ module VagrantPlugins
             flags: flags
           )
         end
+
+        def command_options_for(name)
+          plugin = Vagrant::Plugin::V2::Plugin.manager.commands[name.to_sym].to_a.first
+          if !plugin
+            raise "Failed to locate command plugin for: #{name}"
+          end
+
+          # Create a new anonymous class based on the command class
+          # so we can modify the setup behavior
+          klass = Class.new(plugin.call)
+
+          # Update the option parsing to store the provided options, and then return
+          # a nil value. The nil return will force the command to call help and not
+          # actually execute anything.
+          klass.class_eval do
+            def parse_options(opts)
+              Thread.current.thread_variable_set(:command_options, opts)
+              nil
+            end
+          end
+
+          # Execute the command to populate our options
+          klass.new([], {}).execute
+
+          options = Thread.current.thread_variable_get(:command_options)
+
+          # Clean our option data out of the thread
+          Thread.current.thread_variable_set(:command_options, nil)
+
+          # Send the options back
+          options
+        end
       end
     end
   end